| // Copyright (c) 2011 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| /** |
| * @fileoverview |
| * The webapp reads the plugin's connection statistics frequently (once per |
| * second). It logs statistics to the server less frequently, to keep |
| * bandwidth and storage costs down. This class bridges that gap, by |
| * accumulating high-frequency numeric data, and providing statistics |
| * summarising that data. |
| */ |
| |
| 'use strict'; |
| |
| /** @suppress {duplicate} */ |
| var remoting = remoting || {}; |
| |
| /** |
| * @constructor |
| */ |
| remoting.StatsAccumulator = function() { |
| /** |
| * A map from names to lists of values. |
| * @private |
| * @type Object.<string, Array.<number>> |
| */ |
| this.valueLists_ = {}; |
| |
| /** |
| * The first time, after this object was most recently initialized or emptied, |
| * at which a value was added to this object. |
| * @private |
| * @type {?number} |
| */ |
| this.timeOfFirstValue_ = null; |
| }; |
| |
| /** |
| * Adds values to this object. |
| * |
| * @param {Object.<string, number>} newValues |
| */ |
| remoting.StatsAccumulator.prototype.add = function(newValues) { |
| for (var key in newValues) { |
| this.getValueList(key).push(newValues[key]); |
| } |
| if (!this.timeOfFirstValue_) { |
| this.timeOfFirstValue_ = new Date().getTime(); |
| } |
| }; |
| |
| /** |
| * Empties this object. |
| */ |
| remoting.StatsAccumulator.prototype.empty = function() { |
| this.valueLists_ = {}; |
| this.timeOfFirstValue_ = null; |
| }; |
| |
| /** |
| * Gets the number of milliseconds since the first value was added to this |
| * object, after this object was most recently initialized or emptied. |
| * |
| * @return {number} milliseconds since the first value |
| */ |
| remoting.StatsAccumulator.prototype.getTimeSinceFirstValue = function() { |
| if (!this.timeOfFirstValue_) { |
| return 0; |
| } |
| return new Date().getTime() - this.timeOfFirstValue_; |
| }; |
| |
| /** |
| * Calculates the mean of the values for a given key. |
| * |
| * @param {string} key |
| * @return {number} the mean of the values for that key |
| */ |
| remoting.StatsAccumulator.prototype.calcMean = function(key) { |
| /** |
| * @param {Array.<number>} values |
| * @return {number} |
| */ |
| var calcMean = function(values) { |
| if (values.length == 0) { |
| return 0.0; |
| } |
| var sum = 0; |
| for (var i = 0; i < values.length; i++) { |
| sum += values[i]; |
| } |
| return sum / values.length; |
| }; |
| return this.map(key, calcMean); |
| }; |
| |
| /** |
| * Applies a given map to the list of values for a given key. |
| * |
| * @param {string} key |
| * @param {function(Array.<number>): number} map |
| * @return {number} the result of applying that map to the list of values for |
| * that key |
| */ |
| remoting.StatsAccumulator.prototype.map = function(key, map) { |
| return map(this.getValueList(key)); |
| }; |
| |
| /** |
| * Gets the list of values for a given key. |
| * If this object contains no values for that key, then this routine creates |
| * an empty list, stores it in this object, and returns it. |
| * |
| * @private |
| * @param {string} key |
| * @return {Array.<number>} the list of values for that key |
| */ |
| remoting.StatsAccumulator.prototype.getValueList = function(key) { |
| var valueList = this.valueLists_[key]; |
| if (!valueList) { |
| valueList = []; |
| this.valueLists_[key] = valueList; |
| } |
| return valueList; |
| }; |